Liquidtight carton and method



April 17, 1951 F. D. BERGSTEIN 2,549,048

LIQUID TIGHT CARTON AND METHOD Filed May 9, 1947 2 Sheets-Sheet 1 BY Maa/22m ATTO RN YS.

April 17, 1951 F D, BERGSTE|N I 2,549,048

LIQUID TIGHT CARTON AND METHOD Filed May 9, 1947 2 SheebS-Sheell 2 IN V EN TOR. w/vfwa A55/fas rE/N.

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Patented Apr. 17, 1951 UNITED STATES PATENT OFFICE LIQUIDTIGHT CARTON AND METHOD A Frank Davia ergstein, cincinnati, ohio Application May 9, 1947, Serial No. 746,965

18 Claims. 1

Cartons to which this invention relates nd their principal usefulness as containers for liquids and other materials requiring a sealed condition of the container.

It is an object of the invention to provide ,cheaply a carton which can readily be sealed, and a method for that purpose.

It is an object of the invention to provide a new method for sealing cartons by interior end iiooding, as will hereinafter be set forth.

It is an object of the invention to provide cartons which may be closed and sealed by the user either entirely by hand operations or with the simplest. devices and mechanisms, so that the furnishingcf his product in a sealed carton does not entail any large capital outlay for equipment.

It is an object of my invention to provide a novel type of container for milk, which is a sealed container but may be readily opened and closed, and which has means whereby the level of thevcream line may be determined.

It is further my object to attain all of these features in a knock-down paperboard carton manufactured in the usual way on standard equipment and of no greater cost than conventional cartons not possessing the features set forth above. Y

These and other objects oi the invention, which will be set forth hereinafter, or will be apparent to one skilled in the art upon reading these speciu cationsJ accomplish in those constructions and arrangements of the parts and by those methods ofwhich I shall now describe certain exemplary embodiments. Reference is made to the .drawings which form a part hereof, and in which:

.Figure 1 isa partialplan view 'of a'blank for a liquid container,

Figure 21's a similar view showing the blank in tubed condition.

Y Figure 3 is a vertical longitudinal section with portions in perspective, showing a rst step in sealing the carton. y

Figure 4 is a partialperspective view showing a sealed end of the Acarton after having been opened.

Figure 5 is a Tvertical longitudinal section of the same openedy carton showing a second step` in the effectingof an end seal.

. Figure 6 is a plan View ci a blank for another form of carton falling withinmy invention.

Figure '7 is a similar plan View showing the carton of Figure 6 in tubed condition` Figures 8 to 14` inclusive are partial perspectiveA views showing the various steps in forming the topend closure oi this style of carton.

(Cl. 22B-5.5)

2 Y Figure 15 is a perspective view of the completed carton.

Figure 16 is a partial perspective View showing the top end of the carton in open condition.

Figure 17 is a partial sectional view of the same structure. A In a copending application in my nameventitled Tight Cartons, Serial No. "140,313J filed April 9, 1947, I have shown a method whereby knockdown or folding cartons may after erection be sealed at the ends by end flooding operations. The cartons of the present invention, being primarily designed to hold liquids, are also sealed by end ooding operations, as will hereinafter be described. But in accordance with the teachings herein, I am enabled to effect the sealing in new and improved ways, and attain substantial advantages in structure.

Referring to Figure l, I have shown a blank for an exemplary carton having a series of body walls l, 2, 3 and Il in articulation along score lines which are shown dotted. A glue ap 5 is articulated to the wall 4 in a similar fashion. At the tops of the body walls I provide closure flaps 6, l, 3 and S. These are seal-end closure naps. The two flaps 'l and S of lesser area are designed to be folded iirst. Flap 'E is provided with an opening I0. This registers with an opening Il in the intermediate nap 6. The portion Sa of the flap 3, which will cover these combined openings, is demarked from the remainder of the iiap by a line for severance l2. The flap portion 8a may also be provided with a lip i3 to facilitate lifting.

The body walls l to 4 of the carton shown in Figure 1 will be provided at their bottom ends with suitable closure flaps, preferably of the sealend variety,

The carton will be made oi paperboard suitably proofed in view of the nature of the liquid which is to be transported in it. The nature of the proong does not form a specic limitation upon this invention.

The carton blank shown in Figure l may be tubed in the ordinary way through the use of the ordinary carton folding and gluing equipment. Where the carton is to-holdliquids,V I prefer to tube it with the glue flap 5 lapped outside the free edge ofthe body Wall I as shown in Figure 2. The adhesive used in tubing the carton will, oi course, be one unaffected by the nature of the liquid to be transported. The tubed, knocked-down structure will be shipped to the carton user.

The carton user will erect `the cartonin the usual way, and will; first close the flaps on the Acurement of fiaps I5, I9, I1 and I8.

top end. These, being seal-end fiaps, may be folded with the interposition of suitable adhesive in the usual fashion. It is however advantageous to diminish the adhesion of the portion 8a of the flap 8 to the contiguous portion of the intermediate flap 6, so that, the part 8a can subsequently be raised. This -may be accomplished in a number of Ways, by omitting to coat the part 8a with adhesive, or by printing a portion of the flap 6 with an adhesive-repellent ink.

When the carton has been closed on the top end, it is then inverted andrsealed on that end.

The manner in which this is done is illustrated in the sectional view, Figure 3. With the carton resting on its top end, a liquid sealing substance is introduced as by a spout I4. The nature of the sealing substance is not a specic limitation-upon this invention.

Preferably I employ a sealing substance which is thermoplastic in character and non-brittle when set. By reason of its brittleness parafiin 2,549,048 -j' I "Y g duced through the filling opening 23, and when 'is not ordinarily advantageous, but mixtures of this wax with non-brittle microcrystalline waxes or the latter alone will serve. Excellent results are obtained by using microcrystalline Wax with or without parafn but withA the addition of resin- 5ous substances-such as polybutenes, chlorinated terphenyls and others, Which act to impart Vresilience and strength and increase bond, while still permitting the parting of the coating as hereinafter set forth.- l I am not limited to heat softened materialsY but Vmay instead employ solvent solutions. As will be pointed out, it is advantageous Vin theY practice of my invention to use `a material `for the coating whichV is capable of resealing under heat.

-The sealing substance is introduced in a thin and highly liquid ycondition through the spout .I4 in a quantity sufficient to cover the then-inside bottom of .the carton. It fiows so as tocover the then bottom; and it is of assistance in distributing the thermoplastic material to rock or tilt .the carton prior tothe solidification of the sealing substance. VWarming the end of the carton Will also assist the sealing substance in penetrating all orifices therein. A relatively thin sealing `coating is thus formed over the entire inner end of thecarton, the coating being bonded to end portions of the body walls-thereof.

. The carton may next be closed upon the opposite end, as by the interfoldingrand adhesive se- This may be done in the usual way andwith the usual apparatus while the carton is in the position illustrated in Figure. 3.

The carton is'next up-endedand is opened by lifting the flap portion 8a, as shown in Figure 4. This will be done after the coating I9 has solidified, but it is immaterial whether the coating shall ,have reached a particular stage of hardness. I have discovered that the result of lifting the flap 8a is to open up a pouring opening formed by the mating perforations II! and II in flaps 6 and 1, the sealing substance formerly extending over Vthis opening interiorly of the carton, and joined fto the coating I9, coming out as a plug 23 in adhesive union with the raised flap 8a.

.Y The carton may be reclosed by folding the ap 8a into its original position. The plug 2t of thermoplastic substance accurately fits the opening in the interior sealing coating I9,'and the structure forms an effective, splash-proof reclosure. It may readily be resealed also by applying sufficient heat to the end of the carton to cause edge v'portions of the plug 20 to interfuse and .join With iedge portions of the coating I9.

the carton has been lled to the desired liquid level, it is moved from beneath the filling means, and is reclosed by folding the flap 8a, bringing the plug 20 into closing position as aforesaid. The

i fiap 8oz-may be -adhesively secured in the reclosing position if desired. Normally also it will be desired to reseal the carton by applying heat to interfuse the portions 20 and I9 of the top interior seal. The carton is now in condition to carry its liquid content to theultimate consumer; .He will reopen the carton in the Way already described, reforming the plug 20 which thereafter will serve as a reclosure for the carton as the contents thereof are dispensed from time to time.

In Figures 6 to 17 inclusive I have illustrated the principles of this invention applied to a type of carton especially designed for the retail transportation and distribution of ,milk, although it is susceptible of other uses. Figure 6 illustrates a blank for such a carton having body Walls 24.

25, 25 and 21 and a glue flap 28 in articulation. The lower ends of the body walls are provided with seal-end flaps 29, 3D, 3| and 32. The glue fiap in this instance is a fairly wide member and.

carries an articulated upper extension 33 as shown. At the upper ends of the body walls I locate fiaps 34, 35, 36 and 31. The rstof these is provided with an opening 38 which, in the erected and closed carton, will mate with a similar opening 39 in the flap 31. Flaps 34Vand 36 are short flaps designed to be folded first. The fiap 31 is an intermediate flap.

The iiap 35 is divided transversely by a score line into two parts. The outer part 35a is designed to form a cover panel hinging on the score line 4U. This portion is provided with side flanges 4I and 42 and a front fiange 43. This front flange has articulated'glue flaps 44 'and'45.

For a purpose hereinafter to be described, one of the body walls, for example the wall 215, may be provided with an opening 46 located near the top of the body wall. y

The blank of Figure 6 will be made of any suitable boxboard which is treated to give proofness with respect Yto the liquid for which the carton is designed.

In tubing the carton as shown in Figure 7, the glue flap 28 is positioned on the outside of the wall 24 Iand adhered thereto with a suitable adhesive. The carton may be shipped to the user in the form shown in Figure '7, or withthe addition of a transparent covering for the opening 46, as hereinafter more particularly described.

Figures 8 to 14 inclusive show various steps in formingup the top closure of carton. The first step, as indicated in Figure 8 is that of erecting the carton, or squaring up the body thereof. When this has been accomplished the short fiaps '34 and 36 may be folded inwardly as shown inV asesinas flap- 3;'1. andi. the; portion j 3 5,: of theff` top member,

lthetop Amember is. foldednoyeronto. the'topof; the;

carton as shown in Figure 12. Tnet-portion. 35a of.y the topmember will not beadhered, but; will be; freeto fold or pivoton `the -score` line V40.A

The. front flap `43 on the top memberisnext foldedover against the bodywall-21, as also shown in Figure 12. The glue tabs 44 andv 45A are folded backwardly against theadjacent body walls and with the interposition of suitable adhesive f the Vside cover flanges 4IV and 42 are: foldeddown- VWardly sofas to cause them to adhere to theglue tabs 44 and 45. These steps. are'illustrated in Figures `13 and 14.

The result is a closed Abox havingatitheclosed endza-.hinged coverfmember-with side andfront ,fiangesa This cover memberA may be4 raised, as shownin Figure 16, and when so raised,` `vvill dis; close theglue flap extensionz33 overlying `the `dispensing opening described above. Vposition the. cover member will overlie` the glue flap extension 33 holdingit in positionover the dispensing opening.

The-carton, closed at its upperend, is` now inverted, andan inner seal is formed. at the said end bythe introduction of'a suitable liquid or molten adhesive. The` interior sealing coating is indicated at 41 in Figure 17. When the coating has solidified or hasbecome plastic; andnonliquid,` the carton may be re-inverted, theA top opened as shown in Figuretldandthe glueiiap extension 33 raised. This Will cause a `portion of the coating47 to come away inladhesive union,

with the glue flap extension 33 for-ming' a plug 48 matching the orifice inthe interior tcoating47j. The flaps'ZQ; 30, 3| and 32"of theflower ends'of the carton body `walls may now` be closed: Iand adhesively secured,l whereupon a. bottom sealing coating may be formed' interiorly of the cartonby introducing a` liquid or molten sealing substance through the pouring opening.

' The opening 46 in the bodyl Wall 26, wherefprovided, is preferably covered with .a sheet'of .transparent vplastic'substance 49, adhered to the wall 26 in such away as to: form a seal. Ina carton designed to hold milk, the opening. 46.may. be so located as: to give ai View'.- of the contentsy ofthe carton at the cream line. A' structure of this general characterJi-s set forth in my copending application entitled Sealed Cartons'andMetbod", Serial No. 768,150 filedY August`12, 1947, now Pat'- ent Number 2,543,757. In the cartons of thepres-V ent invention, however, it is` not necessary to seal the ends by sealing substancesV introduced through the? opening 46; Asa consequence, the

sheet'49 of transparent' plastic maybe aixed to .the cartonblank or to theftubedfstructure as an incidentof the manufacture of the'carton, and may with advantage be afXedtotheinnersure face ofthe boxboard.

The carton of Figure 16, closedandsealed on both ends. can next be filled in the `usual fashion through the dispensing opening; Afteri filling, the glue ap extension 33 WilVberefolded,v the plug 48i entering 'the orifice. in thev interior coati ing 41, and forming'.asplashetightnlosure: The carton maybe resealed hermetically by` applying suicient heat to the top end of it to cause'the substance of the Iplug 4-8 to, fuse Iwith. the'substance ofthe coating 41 It will be noted inlthis-form of` carton that a construction is provided in which theactuai closure, comprising` the. glue ap extension` 33 and the plastic plugf4-8 is covered` by a` cap.l oon.- struetionhoomprising thetop member 35e-.i and In` its4 closed thesidesandfront. flanges 41, 42.-,l and,.43. This provides a' completely sanitary construction advantageous in .theretail shipment vand .handling ofi products such as milk.

Modifications may be made. in my invention without departing from the spirit of it. Having thus described my invention in certain exemplaryfembodiments, whatI claim asnew and desire to secure by Letters Patent is:

1. A carton. hav-ing awall, a perforation through said Wall, anv imperforate flap overlying and covering said perforation, and an interior casting of sealing substance of predetermined amount and substantial thickness covering said Wallinteriorly and also that portion of said flap uncovered 4by said perforation, so rthat when said iiap is raised, a portion of saidlcasting substan-f tiallyA Outlined byjthe periphery of said-perforation Will break away from the remainder of said casting and form a plug in adhesive union with saidiflap, said plug being` re-insertable in said y opening. .V

2. In a carton a-tubular body and end closure flaps, certain of said flaps being perforated to provide a dispensing opening for liquids, said end closure. flaps including an imperforate iiap overlying said opening, and a casting of sealing substance of predetermined amount and substantial thickness located interiorly of the end closure formed by said iiaps, entirely covering inner onesof said perforated Vfiaps vand said .additional imperforate flap as disclosed-by the perforatins insaid other flaps, said last mentioned ap beingraisable and said casting being partible along alinesubstantially determined bythe periphery of lsaid perforation to forma plug of seal'ingsub.- stance in adhesive uniontherewith.

3. A- sealed, reclosable` carton having a tubular body and end closurefiaps of which a first folded closureflap andan intermediate fllap have mating, perforations and an outer imperforate flap has a portion covering said mating perforations denedloy a line for severancefrom the re mainder of said flap so as to beseparately liftable, said flaps being in closed position, and a unitary casting of sealing substance of predetermined amount entirely covering the interior surfaces of the end closure formed by said flaps and substantially confined thereto, bonded to end portions of said body Walls,.and bonded directly to said covering portion of said outer ap.

4. The structure claimed in claim 3 in which the other end of` said body is provided withxclosure;iiaps, said .closure naps being in closed position, with acasting of` sealing substance Within thecarton and. covering' said `last mentioned closure; f

5.' A carton having an end closure` and. a' body, a; dispensing opening formed in said` end closure, a' member overlying said dispensing opening, Aand an integral casting of. sealing substance of predetermined amount" and substantial thickness Within said carton entirely coveringthe surface of 4'said closure and the surface of' said last mentioned `member'as exposed by saidopening, and substantially confined` thereto.

6. In a sealed, reclosable carton for liquids, a tubular body, closure flaps at an end of said body, said closure flaps comprising a pair of first` folded'` flaps, an intermediate` flap andA a final folded .ap, one of said first folded flaps and said intermediate flap having mating perforations providing a dispensing opening, a membenoverlying, said perforations, said .lastpfolded flaphavingfa. hinged portioniwith side. andl front 7 anges overlying said perforation, and a unitary casting of sealing substance in the interior of said carton overlying the closure formed by said flaps, extending in an unbroken fashion through said perforation and coating the said overlying member, bonded to end portions of thebody walls of said carton, said casting having sufficient thickness to form a reclosure plug when said overlying member is raised and the portion of said casting adhering thereto Yis broken away from the remainder of said casting. .'7'. The structure claimed in claim 6 including a glue flap, and in which said overlying member Vis an articulated extension on said glue hap.

8. The structure claimed in claim 7 in which one of said body walls has a perforation therein and in which said perforation is covered and closed by a sheet of transparent plastic substance affixed to said body wall.

9. A process of sealing cartons which comprises providing a knock-down carton with a tumeans at one end of the carton comprising a series of flaps adapted to be folded into super- Vposed position, a plurality of said flaps having i Wmating' perforations therein forming a dlspensing opening, another of said aps having a por- 'tion to cover said dispensing opening, erecting 4said carton and closing it on the end last described, thereupon forming over said end with ton, and forming an interior seal thereover by'in- Y bular body and end cl-osure means, said closure l troducing sealing lsubstance through said opening formedin said rst closed end.

10. In a reclosable carton a perforated wall, a liftable member overlying the perforation in said wall, a casting a predetermined amount andsubstantial thickness of sealing substance over the interior surface of said wall, said liftableV member in lifted condition having a plug of sealing substance formed thereon broken away from said A casting and adapted to t into the resultant openf .ing in said casting of sealing substance adjacent the perforation in said wall.

1l. A reclosable carton having a perforated wall, aliftable flap overlying said wall and the perforation therein, a casting of sealing substance .g

of substantial thickness on the interior surface of said wall and terminating substantially at the periphery of said perforation, said liftable flap bearing `a plug of sealing substance adapted to pass through the perforation in said. wall and mate substantially with the perforation in said casting.

12. The structure claimed in claim 11 wherein said casting and plug are of thermoplastic substance capable of interfusion upon the application of heat to the combined structure.

13. A process of making a reclosable carton which comprises providing a carton with a perforated wall and anY articulated closure ap overlying the perforation therein, casting against said wall and said flap from the side opposite said flap al solidiable substance in predetermined amount and substantial thickness so as to bring said substance into adhesive union with said walfand flap, ,permitting said substance to so- 8 lidify, andv thereafter raising said Vflap whereby to fracture said substance and formV a reclosure plug on said ap.

14. A process of sealing cartons which comprises providing a knock-down carton with a tubular body and end closure means, said closure means at one end of the carton comprising a series of flaps adapted to be folded into superposed position, a plurality of said aps having mating perforations therein forming a dispensing opening, another of said flaps having a portion to cover said dispensing opening, erecting said carton and closing it on the end last described, thereupon forming over said end with the carton end down an interior casting of solidifiable sealing substance, covering said closure and extending through said perforation to c-ontact and bond to said overlying flap, lifting said overlying flap whereby to fracture said casting along a line substantially determined by the periphery of said perforation, so that a plug-like element of said casting comes away with said lifted flap, closing the opposite end of said carton,'and forming an interior seal thereover by introducing sealing substance through said opening formed in said first closed end, thereafter lling said carton, and reclosing it so that said plug-like element resumes its position in the said casting, and resealing the carton by applyingr heat to interfuse the plug and casting, the sealing substance being a thermoplastic. i 15. A process of sealing cartons which comprises th'e steps of erecting a knock-down carton having a tubular body and end closure means, the closure means at one end of the carton comprising elements with aligned perforations and a means for coveringv them, closing the carton on fthe end last described, introducing into the carton a molten sealing substance with said end Vin a downward position so as yto cover said closure witha casting Aof, the sealing substance bonded to end portions of the tubular body, thereafter closing the opposite end of said carton and inverting it, lifting the cover element of said previously sealed end and effecting an opening through the said casting, thereafter sealing the last closed en d by depositing thereon a casting of molten sealing substance, filling the Vcarton through the opening in the rst formed casting,

' and thereafter resealing the carton by plugging said opening with a plug of fusible substance interfusible with said casting, and effecting a seal by interfusion.

16. A process of sealing a carton which comprises providing a carton having an end closure with a dispensing opening formed therein, and a member overlying said opening, coating said end closure and said member from the side'opposite said member with a solidiable substance in predetermined amount and substantial thickness so as to bring said substance into adhesive union with said end clcsure and with said mem'- ber, and permitting said substance to solidify, whereby to form a casting thereon, from which casting a reclosure plug will break away when said overlying member is lifted.

1'7. A process of making a reclosable carton which comprises providing a carton having a tubular body and end closure flaps, certain of said flaps being perforated to provide a dispensing opening, another of said naps including a member overlying said opening, closing said flaps justV described, and thereupon covering inner ones of said flaps and said additional member as disclosed by the perforations, witha predetermined amount of solidiiiable substance in substantial thickness so as to bring said substance into adhesive union with said flaps and the exposed portion of said member, and permitting said substance to solidify, whereby to form a casting thereon, from which casting a reclosure plug will break away when said overlying member is lifted.

18. A process of making a reclosable carton which comprises providing a carton having a tubular body and end closure flaps, certain of said flaps being perforated to provide a dispensing opening, another of said flaps including a member overlying said opening, closing said flaps just described, and thereafter covering inner ones of said aps and said additional member as disclosed by the perforations with a coating of solidifiable substance in predetermined amount so as to bring said substance into adhesive union with said flaps and the exposed portion of said member, permitting said substance to solidify so as to form a casting of substantial thickness thereon and thereafter raising said member whereby to fracture said casting along a line determined substantially by the periphery of said perforations, whereby to form a plug of sealing substance on said member.

FRANK DAVID BERGSTEIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,247,237 Doble Nov. 20, 1917 2,059,101 Guenther Oct. 27, 1936 2,074,357 Bergstein Mar. 23, 1937 2,217,142 Stedman Oct. 8, 1940 2,218,670 Bennett Oct. 22, 1940 2,290,185 Hinkle July 22, 1'942V 2,321,050 Seymer June 8, 1943 2,335,865 Lanigan et al Dec. 7, 1943 2,341,845 Mark et al. Feb. l5, 1944 

